weak inversion in analog and digital circuits - Lund Institute of ...

Weak inversion
DRAIN CURRENTEXPRESSION IN WEAK INVERSION
VP-V • -Qi /Cox = 2nUT e UT « 2nUT VG-VT0 VS VD
- -
ID = IS e nUT (e UT - e UT )
IF IR CSEM, E. Vittoz, 2003
VP -VS,D thus: IF,R = IS e UT • Definition: specific current of the transistor: IS = 2nβUT 2
• Introducing V P ≅ (V G -V T0 )/n and I D =I F - I R , this yields:
for I F and I R « I S
page 6
(10 to 300 nA for W=L)